Self-Assembled Silica Gel Networks

Wang, Joseph; Pamidi, Prasad V. A.; Zanette, Dino

doi:10.1021/ja9742747

Cited by 69 publications

(62 citation statements)

References 12 publications

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“…Consistent with the ability of various thiol compounds to form self-assembled monolayers on gold electrodes [43], the chemisorption of MPTMS on gold has been pointed out by several techniques, including X-ray photoelectron spectroscopy [24], infra-red and Raman spectrometries [24], cyclic voltammetry [23,25,27], scanning tunneling microscopy [44], and electrochemical impedance spectroscopy [28]. This was often the starting point to build silica-based thin (or thick) films on the gold surface [24 -26, 28, 34], with improved adhesion in comparison to silica films not formed on the basis of MPTMS [34,45].…”

Section: Self-assembly Of Mptms Versus Condensationmentioning

confidence: 81%

Electrochemically‐Induced Deposition of Amine‐Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic Medium

Walcarius

Sibottier

2005

Electroanalysis

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Well-adherent amine-functionalized porous silica films have been deposited on gold electrodes by combining the selfassembly technology, the sol -gel process, and the electrochemical modulation of pH at the electrode/solution interface. A partial self-assembled monolayer of mercaptopropyl-trimethoxysilane (MPTMS) was first formed on disposable gold electrodes from recordable CDs (Au-CDtrodes). The so pretreated MPTMS-Au-CDtrodes were immersed in a stable sol solution (pH 3) containing (3-aminopropyl)-triethoxysilane (APTES) and tetraethoxysilane (TEOS). Polycondensation of the APTES and TEOS precursors was then achieved by applying a negative potential for a given period of time to generate a local pH increase at the electrode/solution interface and promote the deposition of the amine functionalized silica film adhering well to the electrode surface owing to the MPTMS monolayer acting somewhat as a "molecular glue". Various parameters affecting the electrodeposition process have been studied and the film permeability to redox probes in solution was characterized by cyclic voltammetry. The amine-functionalized silica film electrodes were then applied to the preconcentration of copper(II) species prior to their electrochemical detection by anodic stripping differential pulse voltammetry. Getting high sensitivity has however required the application of an electrochemical pre-activation step as the majority of the organo-functional groups were in the form of ammonium moieties (because the film was prepared from an acidic sol). This was achieved by applying a sufficiently negative potential to the electrode surface to reduce protons and increase consequently the amine-to-ammonium ratio within the film and, thus, the efficiency of the precocentration process. The resulting device was then optimized for copper(II) determination in hydroalcoholic medium, giving rise to a linear response in the 0.1 -10 mM concentration range.

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Section: Self-assembly Of Mptms Versus Condensationmentioning

confidence: 81%

Electrochemically‐Induced Deposition of Amine‐Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic Medium

Walcarius

Sibottier

2005

Electroanalysis

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“…Among the various reagents used for electrode modifications, (3-mercaptopropyl) trimethoxysilane (MPS) has attracted attention as an excellent electron transfer mediator due to some unique characteristics. It exhibits dual behavior both as thiols and as sol-gel functionalities [22,23]. The thiol functional group in MPS is capable of coordinating with copper specifically, thus copper can be complexed with MPS and used as an electrocatalyst.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous analysis of nitrate and nitrite in a microfluidic device with a Cu-complex-modified electrode

2006

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A CE microsystem coupled with a microchip and a copper-(3-mercaptopropyl) trimethoxysilane (Cu-MPS) complex-modified carbon paste electrode (CPE) was developed for the simultaneous analysis of nitrite and nitrate. The method is based on the electrocatalytic reduction of both analytes with the modified electrode. The Cu-MPS complex was characterized by voltammetric, XPS, and FT-IR analyses. Experimental parameters affecting the sensitivity of the modified electrode were assessed and optimized. The best separation was achieved in a 60 mm separation channel filled with a 20 mM acetate buffer of pH 5.0 containing 3.0 mM CTAB at separation field strength of -250 V/cm within 90 s. The detection potential for the simultaneous analysis of nitrite and nitrate was found to be -225 mV versus Ag/AgCl. A reproducible response (RSD of 3.2% (nitrite) and 2.8% (nitrate), n = 8) for repetitive sample injections reflected the negligible electrode fouling at the modified CPE. The interference effect was examined for other inorganic ions and biological compounds. A wide hydrodynamic range between 0.25 and 120 microM was observed for analyzing nitrite and nitrate with the sensitivities of 0.069 +/- 0.003 and 0.065 +/- 0.002 nA/microM, and the detection limits, based on S/N = 3, were found to be 0.09 +/- 0.007 and 0.08 +/- 0.009 microM, respectively. The applicability of the method to water and urine samples analyses was demonstrated.

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“…Schiffrin et al [18 -20] investigated the self-organization of nanosized Pt particles onto Au surfaces; Ohgi et al [21 -22] deposited Au onto self-assembled monolayers of thiol and dithiol molecules on Au substrates. Wang et al [23] designed a novel procedure to assembling silica gels onto a gold electrode via the direct coupling of sol -gel and selfassembly technologies with (3-mercaptopropyl) trimethoxysilane (MPTMS). Shen et al [24] proposed a simple SAM method to fabricate three-dimensional networks of MPTMS-based on Au substrates, which provides efficient attaching sites for gold nanoparticles and a variety of biomolecules.…”

Section: Introductionmentioning

confidence: 99%

Self‐Assembly Film of Zeolite Y Nanocrystals Loading Palladium on an Au Electrode for Electrochemical Applications

Jiang¹,

Si²,

Chen³

et al. 2006

Electroanalysis

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Nano-scale zeolite Y crystals were synthesized, and palladium nanoparticles were prepared in the supercage of the zeolite by "ship-in-a-bottle" approach. A novel method to fabricate zeolite-modified electrode (ZME) loading Pd nanoparticles was developed, in which the zeolite Y loading Pd 2þ ions was self-assembled on (3-mercaptopropyl) trimethoxysilane-attached Au surface to form the stable and density packed multilayers (SAM-ZME). The structures of zeolite Y and the SAM-ZME were investigated by using TEM, XRD and SEM techniques. Pd 2þ ions in the SAM-ZME were converted into Pd nanoparticles (Pd n 0 ) by two steps consisting of the electrochemical reduction as well as the succeeding admission and release of CO. The redox couple [Fe(CN) 6 ] 3À/4À was used to probe the electron-transfer barrier properties during self-assembling process. Moreover, the special properties of the SAM-ZME loading Pd n 0 were studied by using cyclic voltammetry and CO-probe in situ FTIR spectroscopy. The results illustrated that Pd n 0 in the SAM-ZME exhibits higher electrocatalytic activity for oxidation of adsorbed CO than that of ZME prepared in our previous study by zeolite coating method. The present study is of importance in design and preparation of SAM-ZME, which poccesseses excellent properties for the immobilization of electrocatalysts or biomolecules.

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Self-Assembled Silica Gel Networks

Cited by 69 publications

References 12 publications

Electrochemically‐Induced Deposition of Amine‐Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic Medium

Electrochemically‐Induced Deposition of Amine‐Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic Medium

Simultaneous analysis of nitrate and nitrite in a microfluidic device with a Cu-complex-modified electrode

Self‐Assembly Film of Zeolite Y Nanocrystals Loading Palladium on an Au Electrode for Electrochemical Applications

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